The present invention relates to devices and methods for administering or dispensing selected amounts of substances, including devices and methods used in medicine. More particularly, it relates to devices and methods for delivering a selected amount or dose of a substance, including dosing devices that provide for a semi-automated priming function, and to the dosed administration of an injectable product.
Devices for the dosed administration or delivery of a medication, such as insulin, hormones, and the like, are well known. Such devices include injection devices, including those known as injection pens. An injection pen is an injection device that a patient, for example a diabetic, can operate in order to self-administer a desired dose of insulin. Typically, such injection pens possess a dosing knob that projects from an opening of a housing. For the administration of an injection, the dose to be administered is selected or set by means of the dosing knob. Through the turning of the dosing knob, a drive means is preset. For the injecting, the dosing knob is then moved forward from a first end position slightly into the housing, until a second end position is reached. In the process, the preset amount of the product to be injected is administered. Further, in the process of injecting a drive means is moved forward and acts on a piston, which acts on the injectable product in an ampoule, so that the medication is displaced from the ampoule and expelled or delivered via a cannula.
After administration of the medication, it is typically necessary to prepare the injection pen for a new, subsequent injection by carrying out a priming process. As is known, in this process the cross-section or central bore of the injection cannula is deaerated as well as freed of residual materials through the expelling of a certain small amount of the product to be injected without an injection being carried out.
This priming process, which may be referred to more simply as priming, is an additional operating step for a patient that has to undertake an injection, which step must not be forgotten if an optimal injection after the priming is to be obtained. In at least one known dosing device or injection pen, a priming is effected in that, through the rotating of an adjusting section, a changeover from an administration position into a priming position is achieved. This adjustment must be reset again for a subsequent administration or injection. This requires an additional effort and additional attention of the patient. It is precisely in stressful situations, when a quick insulin injection must absolutely take place, that the patient can inadvertently disregard or improperly carry out this operating process.